I think you are calculating AA stacked graphite, not bilayer graphene. Please recheck your input.
2015-05-01 11:14 GMT+02:00 Jaehwan Kweon <[email protected]>: > Dear all Siesta users, > > I am calculating band structure of double layer graphene (AA stacking) > From the monolayer's code, I just added two atoms on top of the structure. > > Result pdf files of MLG(monolayer graphene) and BLG(bilayer graphene) are > attached. I tracked Gamma(0) - K(0.901) - M(1.351) - Gamma(2.132) point > while drawing band lines. > > Comparing with reference (DOI: 10.1039/C2NR30823A > <http://dx.doi.org/10.1039/C2NR30823A> (Communication) *Nanoscale* > <http://dx.doi.org/10.1039/2040-3372/2009>, 2012, *4*, 4443-4446) > > The problems are > 1. Band energy of electrons is on the order of 10 (so high, usually few eV) > 2. Bilayer graphene band structure does not correspond with reference > 3. As I know, in case of AA stacking, only k point must show big > difference (Diamond shape in k point band lines) > 4. Doubt about potential V(r) from PAO.basis., is it properly set? Can I > change cut off radius randomly? > > Below is code of BLG > Any kinds of comment would be grateful and it would be greatly helpful if > someone can correct code for my future study. > > ############################################################## > > SystemName bigraphene > SystemLabel bigraphene > NumberOfAtoms 4 > NumberOfSpecies 1 > > %block ChemicalSpeciesLabel > 1 6 C > %endblock ChemicalSpeciesLabel > > %block PAO.Basis > C 2 -0.12072 > n=2 0 1 E 128.52695 3.40412 > 3.93 > n=2 1 1 E 76.78391 3.23752 > 4.11407 > %endblock PAO.Basis > > %block kgrid_Monkhorst_Pack > 10 0 0 0.5 > 0 10 0 0.5 > 0 0 10 0.5 > %endblock kgrid_Monkhorst_Pack > > MeshCutoff 210. Ry > > LatticeConstant 2.46 Ang > > %block LatticeVectors > 1.00000 0.000000 0.00000 > 0.50000 0.866025 0.00000 > 0.00000 0.000000 1.00000 > %endblock LatticeVectors > > AtomicCoordinatesFormat ScaledByLatticeVectors > %block AtomicCoordinatesAndAtomicSpecies > 0.3333333 0.3333333 0.000000 1 > 0.6666667 0.6666667 0.000000 1 > 0.3333333 0.3333333 1.268292 1 > 0.6666667 0.6666667 1.268292 1 > # z value is from (interlayer > distance~3.4 / lattice const) > %endblock AtomicCoordinatesAndAtomicSpecies > > SpinPolarized false > xc.functional LDA > xc.authors CA > > SolutionMethod diagon > > MaxSCFIterations 200 > DM.MixingWeight 0.20 > DM.Tolerance 1.d-5 > DM.NumberPulay 4 > ElectronicTemperature 300 K > > DM.UseSaveDM true > UseSaveData true > > WriteMullikenPop 1 > writecoorxmol .true. > > %block BandLines > 1 0.000000 0.000000 0.0000 \Gamma > 30 0.666667 1.154700 0.0000 K > 30 1.000000 0.577350 0.0000 M > 20 0.000000 0.000000 0.0000 \Gamma > %endblock BandLines > > ############################################################## > > Thank you! > -- > Jaehwan Kweon > Sungkyunkwan University(SKKU) & SKKU Advanced Institute of > Nanotechnology(SAINT) > 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi 440 - 746, Republic of Korea > > Office:+82-31-299-4871 > C.P.#: 010-5145-8388 > E-mail: [email protected] > [email protected] > -- Kind regards Nick
